The Russian Federation is experiencing the fastest growing HIV/AIDS pandemic in the world. In less than a decade, the reported number of HIV infections across Russia's 89 administrative territories grew by a factor of 300, from less than 200 in 1994 to over 50,000 in 2002. In 1998, the Center for Interdisciplinary Research on AIDS (CIRA) at Yale University, in collaboration with the Biomedical Center and St. Petersburg State University (SPSU) in St. Petersburg, began an AIDS International Training and Research Program (AITRP) focused on HIV prevention and covering a wide range of public health-related disciplines. Now in its sixth year, the Yale University AITRP has provided mentorship, research support, and lasting partnerships to 27 Russian trainees primarily in biology, medicine, sociology, and psychology, and enabled them to apply their knowledge in research and teaching positions upon their return home. This proposal seeks support to continue training a cadre of researchers in a broader spectrum of biological, quantitative, social, behavioral, and political sciences to build capacity in Russian institutions to address many important researchable issues that need resolution to mount a multi-faceted response to the expanding HIV/AIDS epidemic. Mounting an effective response to the HIV/AIDS epidemic in Russia also requires a well-functioning health system that provides effective preventive and care services to diverse populations in different regions. There is no school of public health in Russia to provide this training and no institution that offers a Master of Public Health (MPH) degree. This proposal also seeks to continue building an MPH program at SPSU, a collaborative effort begun in 2002 and led by the Yale AITRP, as a critical step in preparing a new generation of Russian leaders who will spearhead local, regional and national efforts for the protection and improvement of public health, including those required for prevention and care of HIV infection.